Random thought: if you want players to be able to come back to your game over the course of their life, it is even more desirable than normal if the rules are as simple as possible (while maintaining depth of course). This is because it is a reasonable expectation is that they are going to have to remember or relearn the rules when they come back to your game later, or at the very least have a good enough sense of what the rules of the game are like in order to be drawn back in.